Finite element method modeling of temperature gradient-induced Cu atomic thermomigration in Cu/Sn/Cu micro solder joint

Predicting the growth of interfacial intermetallic compounds (IMCs) under temperature gradient (TG)-induced atomic thermomigration (TM) in micro solder joint is an important aspect for improving the reliability of packaged devices. In this paper, we propose a new model based on finite element method (FEM) to simulate the Cu concentration distribution and the diffusion flux for the cold end IMC formation in Cu/Sn/Cu micro solder joints under TG with different preferred beta-Sn grain orientation. It is confirmed that the orientation of beta-Sn grains had a great effect on the growth rate of the cold end IMC. Meanwhile, the orientation of beta-Sn grains also affected the time when the Cu concentration distribution reached a steady state, but not the final Cu concentration values at the same positions after reaching the steady state. By comparing the simulation results with the experimental data from literature, the proposed FEM model was proved to be reliable for analyzing the atomic concentration field and the diffusion flux for IMC formation in Sn-based micro solder joint under TG.

Automated summary

In this paper, a new model based on finite element method (FEM) was proposed to simulate the growth of interfacial intermetallic compounds (IMCs) under temperature gradient (TG)-induced atomic thermomigration (TM) in micro solder joint. The study found that the orientation of beta-Sn grains has an effect on the growth rate of IMCs and the time it takes for the Cu concentration distribution to reach a steady state.